Navigation systems have been developed to provide route and geographical information for directing a mobile user to one or more destinations. These systems are typically being delivered in two primary forms: a self-contained autonomous configuration, and a mobile client and fixed server configuration using some wireless communications means.
An autonomous navigation system provides a single unit comprising a map database, location sensor, user interface, and guidance functions. These types of systems provide everything that is needed to provide navigation and automated guidance in one package without any external data or support. This configuration benefits in terms of robustness in that, being autonomous, it can operate almost anywhere for which it has map data. Recent advances have augmented these types of systems with real-time information, such as traffic, events, and road construction information using wireless data communications. These systems have begun to proliferate in Europe, Japan, and in the U.S., but have been slow to become standard equipment due to the expense of each system, most costing $1500 or more.
While these systems provide a high-quality navigation experience, they are limited by their relative high cost, and by the currency of their information. The primary drawback of autonomous navigation systems is the need to have all map and geographic information integrated as part of the system. This information is typically stored on a CD-ROM or DVD depending upon the detail and geographic region covered, and must be updated periodically to stay current with changes in the road network as well as to provide new points of interests. By storing the information in the navigation system, the cost of the system is higher due to the extra physical equipment and processing requirements. Additionally, the data has a tendency to go out of date. These systems also tend to be bulky and not well suited for non-vehicular navigation and guidance, such as pedestrian navigation.
In response to the limitations of autonomous navigation, another type of navigation system was developed, termed ‘off-board’ navigation, in which a server houses the map and route calculation functions, such that client devices using wireless communications can access the latest map and other navigation-related information without needing to store large amounts of data locally. By locating the information centrally, the data is much more easily maintained and integrated with other dynamic data, such as traffic and road construction information, when compared to autonomous systems. Using this ‘off-board’ configuration, low-cost devices such as portable/laptop computers and PDAs (personal digital assistants) can be used to provide navigation information so long as they have a location sensor (e.g., GPS) and a wireless connection. These types of systems provide the same general functionality as an autonomous system but delegate the processor-intensive route calculation and map functions to the server, which can provide these functions for multiple devices concurrently. Off-board navigation creates low-cost, highly portable navigation and guidance solutions.
A typical navigation scenario using off-board navigation comprises the following steps. Using a client device, a user specifies selection criteria for a route, including one or more destinations, the type of route (e.g., fastest, shortest, scenic), and other personal preferences. A client device transmits the route request to the navigation server, which calculates the route between the client device's current location and the specified destinations. Additionally, other interactions between the system and user may be required to resolve any information not understood by the server, such as an improper address entry or a point-of-interest selection. Following a successful route calculation, the information is delivered to the client device, which either displays the resulting navigation information to the user or processes the information by a local guidance function on the client device.
Though ‘off-board’ navigation systems represent a significant step over autonomous navigation systems, they tend to be very limited in their usefulness as they operate only in areas with wireless communications. Implementations of these systems have resulted in highly proprietary data and communications protocols in order to move information efficiently between the client device and server. As a result, these systems are fairly inflexible and support only a limited number of configurations, devices, and features. In addition, these systems are unable to degrade gracefully when communications break down, as they rely heavily upon the server for continuous navigation information.
A problem with both types of navigation systems is their tendency to be limited to a single user or a single navigation activity. Both lack the ability to incorporate other navigation activities, such as tracking information or guidance information, where other individuals or systems may coordinate navigation together to achieve a common result.
Though both types of navigation systems provide useful guidance and navigation functions, they are limited by platform requirements and propriety implementations. There is a need to blend and balance the two approaches to form a distributed solution that can operate in both configurations as well as others, thereby gaining their respective advantages. With the proliferation of the Internet and associated wireless Internet, a more distributed and platform-independent approach is needed wherein the navigation system's core functions are defined and implemented such that the communications and platform requirements are encapsulated and isolated. This will allow the system to be defined and operated in a logical configuration without explicit knowledge of the physical configuration. There is a further need for the system to adapt, and to support intermittent communications, where one or more parts of the navigation system may be unable to communicate with the other parts, yet still provide their designated function. In addition, the system should be robust and degrade gracefully in the event of unexpected problems.
A useful advance over current systems that is needed would be a navigation system that is dynamically configurable and deployable across various types of devices using standard networking technologies. Both the software implementation and data formats should be defined using open standards such as JAVA, C++, and XML, such that they provide maximal platform independence and integration flexibility. The navigation system would also support multiple device configurations where the navigation system functions are deployed on three or more devices.
Another useful advance would be to provide navigation functionality where multiple parties coordinate navigation activities. Navigation information for one user would be shared and integrated in navigation information for other parties, and provide enabling scenarios such as ‘follow-the-leader’, fleet dispatch, and tracking. There is a need to provide relative guidance, where one vehicle or navigable object is guided with respect to another navigable object.
Yet another useful advance over prior art would be a navigation system that is easy to extend and integrate with other systems without requiring significant engineering and development. A method and system for distributed navigation and automated guidance that solves the preceding problems and addresses the specified needs would be a useful and novel advance over the prior art.